Although the use of mathematical models and quantitative methods in geography accelerated in earnest with the development of quantitative geography and regional science in the late 1950s, such techniques had already made their way into the mainstream of physical geography much earlier. Today, mathematical models and quantitative methods are used in a number of subfields in geography with their proliferation being aided, in part, by the widespread use of remote sensing, geographic information systems (GIS), and computer-based technology. As a consequence, geography as a whole has witnessed a new growth in the development of models and quantitative methods over the last decade, and it is this growth that we seek to elucidate here. Highlighting the advances in the use of models and methods in geography is a difficult undertaking. Such techniques are so widely used in GIS and remote sensing that many developments in these areas also could be considered in this chapter. Moreover, modeling and quantitative techniques are so strongly integrated within some geographic subfields (e.g. climatology and geomorphology, economic and urban geography, regional science) that it is often difficult to separate technique development from application. This is illustrated by the fact that many members of the Association of American Geographers who frequently use and develop quantitative techniques and models are not active participants in the Mathematical Models and Quantitative Methods Specialty Group, choosing instead to favor specialty groups with a more topical, rather than methodological, focus. In a very real sense, the quantitative revolution has been completed in many subfields of geography, with the goals and aims of the revolutionaries having long since passed into the mainstream. Furthermore, geographers who are involved with quantitative methods and mathematical models are extremely diverse in their interests and applications— they contribute to an extremely wide variety of disciplines. While they excel at spreading the geographic word to other disciplines, summarizing their multifarious contributions is nearly impossible. The rather trite statement, “Geography is what geographers do,” seems to apply strongly here. Geographers are largely a collection of individuals who, although united by their interest in spatial models and methods, are unique in the ways that they make contributions to various fields.